It's hard to do irreparable damage to the steel of a knife. It's just an inert lump of metal. But you could fuck up the handle. Theoretically, the detergent could dull your edge. If you don't isolate your knife and it rattles around, that'll definitely dull it. Mostly: it should only take a couple seconds to clean off your knife in the sink.

> It's hard to do irreparable damage to the steel of a knife.

Sadly not impossible, I've 'lost' (they're still in the back of a drawer) two good knives to idiots attempting to pry apart frozen chops and steaks .. each case snapped a good inch from the tip.

Not damage from a dishwasher and not damage the edge I realize, but worth mention as a tale of caution.